Roll-style fabric awnings, so-called “roll awnings,” are commonly provided on recreational vehicles, travel trailers, mobile homes, and the like, and are also usable with fixed structures such as, for example, buildings. Such awnings generally consist of a rotating roller having a sheet of awning fabric or canopy attached and wound thereon. The awning is kept fully rolled up on the roller while the vehicle is configured for traveling. The roller is supported at its ends by support arms for movement between a retracted or stowed position, wherein the roller is disposed adjacent the-wall, and an extended or deployed position, wherein the roller is extended out away from the wall. Once the awning is extended, it is commonly known in the art to lock the support arms using any number of manually-actuated means, such as locks, clasps, straps, adjustment knobs, and the like. However, some users, such as young users, elderly users, or handicapped users may experience difficulty in using manually-actuated locking mechanisms. Thus, there is a need for an improved self-engaging locking mechanism that can avoid these problems.